After destroying more than 135 U.S. tons of mustard agent, the Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) continues to show progress in its neutralization process.

“The neutralization process has been highly successful at PCAPP,” said Greg Mohrman, site project manager. “Neutralization is the chemical process by which we actually destroy the mustard agent.”

After mustard agent is drained from munitions, it is fed into reactors and mixed vigorously with hot water. The chemical reaction is called hydrolysis and the liquid obtained from the neutralization process is referred to as hydrolysate, Mohrman said.

Sodium hydroxide, a caustic, is then added to the agent hydrolysate mixture to neutralize the acid and raise the pH to a range of 10 to 12. The chemical reactions produce an acid and thiodiglycol (TDG). Agent hydrolysate consists mostly of water, TDG and salts, said Brian Ramdwar, laboratory operations branch manager, PCAPP.

“PCAPP must meet stringent analytical protocols to determine we have completely destroyed the agent,” Mohrman said. “Inspectors from the Organisation for the Prohibition of Chemical Weapons are on site and ensure we are in full compliance with the international treaty to destroy the mustard.”